If you know someone that uses an optical mouse, place a small post it note over the eye of the mouse. When your victim tries to use their mouse it won't work. When they decide to look underneath it, they will see a small posted that reads, "April Fools"

Ypto Ypto...errr!!! TYPO!
Be careful with this one, as to not ruin the keyboard. All you have to do is simply and very carefully remove a few keys and switch them around. If your victim is one of those "look up and down" typers. He or she will be very confused while trying to get work done.

Where are those paper clips?
Make a few copies of paper clips then put those copies back inside the paper tray. Whoever uses the copier next will get their copies with those paperclips on them and will look all over trying to hunt them down.

Phone Label Swap
Change the speed dial labels on office phones. It will piss off your co-worker when he is trying to call tech support but instead speed dials the courier.

Self Recognition Prank
Without disguising your voice, compliment yourself over the office intercom. Compliment yourself on a just completed task or give yourself the rest of the day off.

Stale Donuts
About a week before the prank, buy a box of donuts. Keep them in the refrigerator with the top open so they can dry out. On the day of the prank, place the box of donuts near the office coffee pot so anyone with a morning sweet tooth can indulge.

Pick Up The Entire Phone
Wrap a very small piece of wire around the phone cord so both ends are tied together. When the phone rings and your victim goes to pick up the receiver, he will up with the entire phone base with it.

Confusing Drawers
Before your co-worker arrives at the office remove his desk drawers and switch them around. He will definitely scratch his head over this one. Hint: In case you cannot remove the drawers, just remove the items and swap them

Pen Swap
Take all of your co-workers pens and replace them with your pens that your glued caps on to the night before. He will not be able to take the caps off to use the pens.

Old Toy
Use an old toy that has a button which is used to activate sound. Such as a baby crying. Then tape it to the back of the victims desk drawer, but don't close it completely, leave it open just a crack. When your victim decides to close it, he will hear the annoying sound and wonder where its coming from.

Something is wrong with the copier!
Leave a copier to print 99 copies at 33% resolution on 8x14 paper.

Upside Down Cup
Fill a cup with water about half way. Then place an index card over the cup. Then turn the cup upside down on your co-worker's desk. Finally, carefully slide the index card out from underneath the cup. Whenever your co-worker decides to pick the cup up, he will be drenched in water.

Auto Correct
Microsoft Word has a feature called 'Auto Correct'. It will auto correct any mispelling such as 'TEH' which will automatically be changed to 'THE'. Anyone can go into the tool and change the words. When your co-worker is away from his desk. Change a few of his common words around.

Hey! I wanted snacks!
Empty boxes of common snacks such as Cheez-Its or Figs and replace them with shredded paper or anything else that will weigh the box down. Then place them in the break room.

Make your own bumper sticker with tape and paper and put it on your co-workers car. Get creative with the message.

Did I Really Park There?
If you have one of those co-workers that parks in the same spot every day, then try this prank. When he isn't paying attention, take his keys and move his car over just one space.

Party Mix
At the next pot luck luncheon. You bring the Chex Party Mix. But get creative, mix in some Pup-eroni dog food snack. Just break them into little pieces and throw them in the same bowl...stir it up and nobody will tell the difference

Intercom Prank
This is a great prank to play on a new co-worker. Every office has a code to use the PA. Lets say the code is 10. Well, just let the new co-worker know that he has a call for him on 10. When he presses 10 he will say "hello this is Dave" ...hello? hellooo? until he realizes he is on the PA intercom

Hide The Chair
When your victim leave the room, hide his chair. When he returns act like you don't know where it is. A great place to hide the chair would be in the opposite sex bathroom

Myra Mains
This is a great prank for a secretary to play on the office jokester. Maybe the secretary needs to get even. Well try this. When your victim is out to lunch, leave him a message that someone named Myra Mains called and needs a call back ASAP. Leave the number to the local coroner's office with the note. Myra Mains, sounds like My Remains.

New Employee Prank
Send a new employee for various mythical items such as: Double sided transparencies, Dehydrated Water, Bucket of compressed air, A one molar solution of water, A stanchion remover, A bucket of steam, A phallopian tube, A long weight (long wait), A short weight, Short circuits, Lightning bolts, Skyhooks, A mattababe (as in what's a mattababe), A dickfore (same as above), A piston return spring, A left handed wrench, hammer, razor..., Agent Orange (paint color), Sparkplugs for a diesel engine, A short/long stand, A chain stretcher, Hydraulic cement bender, and Snowtires for the shopping carts.

New Secretary Prank
Call the new secretary and tell her that you are calling from the local phone company and will be running a test on all the phone lines in the building. Let her know that its very crucial that for the next 10 minutes that nobody uses any phone line or else electrocution will result. Then hang up.

Keep On Ringing
If you know someone that uses a phone with a hook that presses down when the handset is in the cradle, then tape that part down. When the person tries to answer a call it will just keep on ringing and ringin

20+ cups on desk
Fill about 20 or more paper cups up with water, place them next to each other on your victims desk. Then staple them all together, stand back and watch as he/she arrives at work and is clueless about how to go about removing the cups off the desk.

The Zoo called
Call someone at the office while they are away and leave a message saying Mr. Lyon (or Mr. Behr) called and would appreciate a call back. Then leave the phone number for the local zoo on the answering machine for this person to call.

Eating Out Of The Trash Can
Put some of your chips in a clean back on top of the trash can. Then when you and your fellow co-workers are walking past it, grab a hadnfull and eat them in front of them.

Full Blast!
Turn your victim's speaker volume up full blast. He won't know until the next time his computer makes a sound, it will surprise him to death! haha

Screen Capture
Take a screen capture of someone's screen. It would work best if they have a program open. Then save the screen capture as an image and use that as their desktop background picture. It will confuse the heck out of them when they see their desktop icons over their microsoft word.

IT Prank
Send out a memo to everyone explaining that all computers have been infected with the new 'Letter G Virus' and that everything is ok, but for the rest of today nobody can type the letter 'G' or else it will cause even more havoc on the company computer systems.

Fictional Awards
Send out memos congradulating people for dumb reasons. Tell them they won an award. Awards for Best Filer or Paper Sorter, etc.

Person Calls
Send everyone an email memo about the new company policy. No more personal calls at the office and only schedules personal visits. Then give everyone their personal visit time slot. Exmaple: Barbara Smith, visting hours 10:57 AM to 11:01 AM

The Clapper Prank
Plug The Clapper into your co-workers computer so whenever someone claps, the computer will turn off and on.

Monitor Settings
Every day, while your co-worker is away from his desk adjust his monitor settings so the brightness goes down 2%. At a rate of 2% a day from 100%...in about 2 weeks the brightness will drop 20%. See how long it takes him to notice the change.

Fun In The Copy Room
Copy some images of obsene content such as gay porn, then place them back in the copier paper bin.

Copier Paper Fun
Type in giant bold letter "Copier Needs Service Soon" and make a few copies of the page. Then place the papers back inside the copier paper tray.

M and N keys
While your co-worker in the next cubicle is away, switch the M and N keys on his keyboard.

Fake Ads in the Company Newsletter
Use the ad section of your company newsletter to post fake bulletins. Place an ad for Windows 98 software still in box for $500 OBO. or maybe a desperate plea for someone to buy your timeshare condo. Be creative!

On Hold Music
Change the 'On Hold' music that your office uses for the phone system. Put it on a Death Metal station or even better, put it on a foreign language station.